1. Field of the Invention
This invention pertains in general to the field of door control apparatus and in particular to the field of movement control of a sliding marine door which is affected by the rolling and pitching of a boat due to movement of the sea or other body of water within which the boat is in operation.
2. Description of the Prior Art
A number of boat designs include a sliding door between the outside deck of the boat and the inside of a cabin. Such sliding doors are frequently utilized on any type of boat or ship which includes a cabin on the deck thereof. In such applications, a sliding door is preferred over a hinged, swinging type of door because of space requirements and the negative aspects of a hinged door suddenly swinging in either direction due to rolling seas. Indeed, a swinging door could severely injure a person when he or she is trying to enter or exit through such door when the rolling of the boat due to rough seas suddenly swings the door toward the person.
While sliding doors are preferred, they are also subject to rapid opening or closing in an unrestrained condition due to rough seas. Thus, when a sliding door is unlatched, it will slide back and forth in its tracks depending upon the rolling or pitching motion of the boat and the location of the door. The result is that the door slams open or closed with a great deal of force. If a person is attempting to pass through the doorway associated with such a sliding door at the same time the boat is rocking, it is very probable that the person will be injured and the boat be damaged by the rapidly moving edge of the door.
In order to negate the force effects of an unrestrained sliding door, the usual practice is to latch the door either in an open or a closed position. Latching of a sliding door is not, however, a complete solution to the problem. For example, when a latched-shut door is unlatched preparatory to being open to allow a person or persons to pass therethrough, the rocking and/or rolling movement of the boat causes the door to move rapidly in either or both directions. To overcome this effect, the person must hold onto the edge of the door in an attempt to control the forceful motion of the door. Frequently, the person himself is trying to maintain his own balance and trying to control the movement of the door at the same time. Often, the result is a clumsy effort which is not successful and the door may slam against some part of the person causing him serious injury.
With the sliding door latched in an open position, passage therethrough in a safe and orderly manner is assured. But, the negative effects of the door always being open exist. The disadvantages of a latched open door during foul or rainy weather conditions is obvious.
The prior art door movement control apparatus is generally designed or intended to be used with a swinging type of door and whereby the door mechanism is biased in one direction and pressure activated in the other direction. For the most part, the door control apparatus intended for use with a swinging door is not adaptable to a sliding door particularly where the swinging door apparatus includes articulated lever arms. In the category of door control apparatus which is adaptable to a sliding door, that is, those door controls which utilize a piston and cylinder which move in an axial direction, such prior art apparatus do not satisfactorily control the motion of a sliding door on a boat. This is because such door apparatus will bias the door in either the open or closed direction while requiring force to move the door in the other direction. Therefore, with this type of door control apparatus, either a shut door or open door condition is imposed and the opposite condition is achieved by overcoming the biased spring force and the hydraulic pressure force. Accordingly, both an opened and a closed door position is not obtainable with the apparatus of the prior art, nor is a partially opened door condition obtainable.
Accordingly, a primary object of the present invention is to provide a sliding door on a boat or ship with control apparatus which renders the door stable in either an open or a closed condition, or any partially opened or partially closed condition therebetween.
Another object of the present invention is to provide a sliding door on a boat or ship with control apparatus whereby a constant force may be used to open or close the door from either position to the opposite position.
Another object of the present invention is to provide a sliding door on a boat or ship with control apparatus which prevents the door from slamming open or closed as a result of rolling or pitching motion of the boat or ship.
The above-stated objects as well as other objects which, although not specifically stated, but are intended to be included within the scope of the present invention, are accomplished by the present invention and will become apparent from the hereinafter set forth Detailed Description of the Invention, Drawings, and the claims appended herewith.